It is known as disclosed in U.S. Pat. Nos. 4,325,431 and 4,454,913 to use a hydraulically actuated equalizing valve for equalizing the pressure above and below a subsurface safety valve prior to opening the safety valve. While this protects the main valve in the subsurface safety valve the equalizing valve is subject to failure as a result of the erosion and flow cutting of the equalizing valve element and seat due to the high pressures and high velocities flowing through the equalizing valve.
The present invention is directed to the combination of an improved equalizing system for use with a subsurface safety valve which controls the pressure drop and velocity of the fluid flow through the equalizing system for preventing erosion and allowing an increased life and dependability of the equalizing valve.